Improve performance for icinga::Deserialize.

Refs #5327

lib/base/serializer.cpp

@@ -161,21 +161,24 @@ static Object::Ptr DeserializeObject(const Object::Ptr& object, const Dictionary
 	if (!instance)
 		instance = type->Instantiate();
 
-	for (int i = 0; i < type->GetFieldCount(); i++) {
-		Field field = type->GetFieldInfo(i);
+	BOOST_FOREACH(const Dictionary::Pair& kv, input) {
+		if (kv.first.IsEmpty())
+			continue;
+
+		int fid = type->GetFieldId(kv.first);
+	
+		if (fid < 0)
+			continue;
+
+		Field field = type->GetFieldInfo(fid);
 
 		if ((field.Attributes & attributeTypes) == 0)
 			continue;
 
-		Value value = input->Get(field.Name);
-
-		if (value.IsEmpty())
-			continue;
-
 		try {
-			instance->SetField(i, Deserialize(value, attributeTypes));
+			instance->SetField(fid, Deserialize(kv.second, attributeTypes));
 		} catch (const std::exception&) {
-			instance->SetField(i, Empty);
+			instance->SetField(fid, Empty);
 		}
 	}
 

lib/base/utility.cpp

@@ -705,12 +705,18 @@ String Utility::GetThreadName(void)
 	return *name;
 }
 
-unsigned long Utility::SDBM(const String& str)
+unsigned long Utility::SDBM(const String& str, size_t len)
 {
 	unsigned long hash = 0;
+	size_t current = 0;
 
 	BOOST_FOREACH(char c, str) {
+		if (current >= len)
+			break;
+
 		hash = c + (hash << 6) + (hash << 16) - hash;
+
+		current++;
 	}
 
 	return hash;

lib/base/utility.h

@@ -102,7 +102,7 @@ public:
 	static void SetThreadName(const String& name, bool os = true);
 	static String GetThreadName(void);
 
-	static unsigned long SDBM(const String& str);
+	static unsigned long SDBM(const String& str, size_t len = String::NPos);
 
 	static int CompareVersion(const String& v1, const String& v2);
 

tools/mkclass/classcompiler.cpp

@@ -21,6 +21,8 @@
 #include <iostream>
 #include <fstream>
 #include <stdexcept>
+#include <map>
+#include <vector>
 
 using namespace icinga;
 
@@ -77,6 +79,27 @@ void ClassCompiler::HandleCode(const std::string& code, const ClassDebugInfo& lo
 	std::cout << code << std::endl;
 }
 
+unsigned long ClassCompiler::SDBM(const std::string& str, size_t len = std::string::npos)
+{
+	unsigned long hash = 0;
+	size_t current = 0;
+
+	std::string::const_iterator it;
+
+	for (it = str.begin(); it != str.end(); it++) {
+		if (current >= len)
+                        break;
+
+		char c = *it;
+
+                hash = c + (hash << 6) + (hash << 16) - hash;
+
+                current++;
+        }
+
+        return hash;
+}
+
 void ClassCompiler::HandleClass(const Klass& klass, const ClassDebugInfo& locp)
 {
 	std::vector<Field>::const_iterator it;
@@ -136,11 +159,47 @@ void ClassCompiler::HandleClass(const Klass& klass, const ClassDebugInfo& locp)
 
 	std::cout << ";" << std::endl << std::endl;
 
-	int num = 0;
-	for (it = klass.Fields.begin(); it != klass.Fields.end(); it++) {
-		std::cout << "\t\t" << "if (name == \"" << it->Name << "\")" << std::endl
-			<< "\t\t\t" << "return offset + " << num << ";" << std::endl;
-		num++;
+	std::map<int, std::vector<std::pair<int, std::string> > > jumptable;
+
+	int hlen = 0, collisions = 0;
+
+	do {
+		int num = 0;
+
+		hlen++;
+		jumptable.clear();
+		collisions = 0;
+
+		for (it = klass.Fields.begin(); it != klass.Fields.end(); it++) {
+			int hash = static_cast<int>(SDBM(it->Name, hlen));
+			jumptable[hash].push_back(std::make_pair(num, it->Name));
+			num++;
+
+			if (jumptable[hash].size() > 1)
+				collisions++;
+		}
+	} while (collisions >= 5 && hlen < 8);
+
+	if (!klass.Fields.empty()) {
+		std::cout << "\t\tswitch (static_cast<int>(Utility::SDBM(name, " << hlen << "))) {" << std::endl;
+
+		std::map<int, std::vector<std::pair<int, std::string> > >::const_iterator itj;
+
+		for (itj = jumptable.begin(); itj != jumptable.end(); itj++) {
+			std::cout << "\t\t\tcase " << itj->first << ":" << std::endl;
+
+			std::vector<std::pair<int, std::string> >::const_iterator itf;
+
+			for (itf = itj->second.begin(); itf != itj->second.end(); itf++) {
+				std::cout << "\t\t\t\t" << "if (name == \"" << itf->second << "\")" << std::endl
+					<< "\t\t\t\t\t" << "return offset + " << itf->first << ";" << std::endl;
+			}
+
+			std::cout << std::endl
+				  << "\t\t\t\tbreak;" << std::endl;
+		}
+
+		std::cout << "\t\t}" << std::endl;
 	}
 
 	std::cout << std::endl
@@ -178,7 +237,7 @@ void ClassCompiler::HandleClass(const Klass& klass, const ClassDebugInfo& locp)
 
 		std::cout << ") {" << std::endl;
 
-		num = 0;
+		size_t num = 0;
 		for (it = klass.Fields.begin(); it != klass.Fields.end(); it++) {
 			std::cout << "\t\t\t" << "case " << num << ":" << std::endl
 				<< "\t\t\t\t" << "return Field(" << num << ", \"" << it->Name << "\", " << it->Attributes << ");" << std::endl;
@@ -259,7 +318,7 @@ void ClassCompiler::HandleClass(const Klass& klass, const ClassDebugInfo& locp)
 
 		std::cout << ") {" << std::endl;
 
-		num = 0;
+		size_t num = 0;
 		for (it = klass.Fields.begin(); it != klass.Fields.end(); it++) {
 			std::cout << "\t\t\t" << "case " << num << ":" << std::endl
 					  << "\t\t\t\t" << "Set" << it->GetFriendlyName() << "(";
@@ -417,7 +476,8 @@ void ClassCompiler::CompileStream(const std::string& path, std::istream *stream)
 			  << "#include \"base/debug.h\"" << std::endl
 			  << "#include \"base/value.h\"" << std::endl
 			  << "#include \"base/array.h\"" << std::endl
-			  << "#include \"base/dictionary.h\"" << std::endl << std::endl
+			  << "#include \"base/dictionary.h\"" << std::endl
+			  << "#include \"base/utility.h\"" << std::endl << std::endl
 			  << "#ifdef _MSC_VER" << std::endl
 			  << "#pragma warning( push )" << std::endl
 			  << "#pragma warning( disable : 4244 )" << std::endl

tools/mkclass/classcompiler.h

@@ -142,6 +142,8 @@ private:
 	std::string m_Path;
 	std::istream *m_Input;
 	void *m_Scanner;
+
+	static unsigned long SDBM(const std::string& str, size_t len);
 };
 
 }